Reaction rates depend on temperature as well as on the mechanical state. In shock wave initiation, experimental data almost always comprise mechanical measurements such as shock speed, material speed, compression, and pressure, and are accordingly modeled in terms of these parameters. Omission of temperature is one reason why mechanically based reaction rates do not extrapolate well out with the range of states used to normalize them. The model presented addresses chemical processes directly, enabling chemical kinetic data reported in terms of temperature (and at STP, generally) to be used in shock reaction models. We have recently extended a temperature-based modelmore » for use with ANFO-type formulations. Reactive material is treated as a heterogeneous mixture of components, each of which has its own model for response to dynamic loading (equation of state, strength model, reactions.) A finite-rate equilibration model is used to determine the overall response of the mixture to dynamic loading. In this model of ANFO, the ammonium nitrate and the fuel oil are treated as separate components in the unreacted mixture.« less

Cylinder test, Fabry-Perot laser interferometric and detonation velocity-charge diameter experiments were done to determine the detonation reaction zone structures and reaction product equations of state of a family of HMX/AP/ZrH{sub 2}/estane explosives. This experimental data base is used to develop ignition and growth reactive flow models of the detonations waves in these composite explosives. The experiments and calculations clearly demonstrate the Zeldovich-von Neumann-Doering (ZND) structure of the detonation reaction zones which are several millimeters long. The inferred reaction rates imply that the HMX in these formulations reacts first at rates comparable to those measured in other HMX-based explosives and propellants.more » The remaining components of these explosives then decompose at much slower rates. However, this decomposition is rapid enough to contribute to the propagation of the detonation wave and to the total energy delivered in metal acceleration applications. 22 refs., 9 figs.« less